JP5532012B2 - Gas sensor and manufacturing method thereof - Google Patents

Description

  The present invention relates to a gas sensor for detecting a specific gas concentration in a gas to be measured and a method for manufacturing the same.

  Conventionally, an exhaust system such as an internal combustion engine of an automobile is provided with a gas sensor for measuring the concentration of a specific gas such as oxygen or nitrogen oxide in the exhaust gas. As shown in FIG. 11, the gas sensor 9 is formed in a bottomed cylindrical shape, the reference electrode 912 that contacts the reference gas is formed on the inner surface, and the measurement electrode 914 that contacts the gas to be measured is formed on the outer surface. A sensor element 91 that detects the concentration of a specific gas in the gas to be measured, a housing 92 that supports and fixes the sensor element 91 in the gas flow path to be measured, and a sensor element 91. A rod-shaped heater 93 inserted and disposed in the insulator, an insulator 94 made of an insulating material for inserting and holding the base end portion 930 of the heater 93, and holding the heater 93, fixing the heater 93 to the sensor element 91, A cylindrical metal heater holder 95 electrically connected to the reference electrode 912 of the sensor element 91, and electrically connected to the reference electrode 912 via the heater holder 95. A reference-side signal line 98, at least comprises sensors and a measurement side signal line 99 electrically conductive to the measuring electrode 914 is known (see Patent Documents 1 and 2).

As the heater holder 95, various shapes have been developed. Conventionally, in the gas sensor 9, for example, a cylindrical heater holder 95 to which the heater 4 is assembled is disposed in contact with the end surface 945 on the base end side of the insulator 94.
Specifically, the separator receiving portion is formed on the internal electrode connecting bracket (heater holder) so as to protrude outward from the peripheral edge of the rear end, and the end face of the partition wall portion of the ceramic separator (insulator) is formed on the separator receiving portion. A sensor having a contact configuration has been developed (see Patent Document 1).
Further, a sensor having a configuration in which a sensor terminal member (heater holder) and a separator (insulator) are arranged in contact with each other has been developed (see Patent Document 2).

Japanese Patent No. 3756005 JP 4047919 A

  However, when the heater holder 95 is arranged in contact with the end surface 945 on the base end side of the insulator 94, it is difficult to determine the positional relationship between the two. In particular, it is difficult to determine the position of the gas sensor 9 in the radial direction, the axial displacement between the insulator 94 and the heater holder 95 occurs, and axial alignment is necessary. In addition, the heater 93 is formed with a pair of lead wires 931 for conducting electricity to the heater 93. As described above, since alignment is difficult, the position of the heater holder 95 that holds the heater 93 during assembly is positioned. The insulator 94 is easily shaken, and the lead wire 931 of the heater 93 may be bent at the time of contact.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a gas sensor that can easily assemble an insulator and a heater holder, and a manufacturing method thereof.

The first invention comprises an ion-conducting solid electrolyte body formed in a bottomed cylindrical shape, having a reference electrode in contact with the reference gas formed on the inner surface and a measurement electrode formed in contact with the gas to be measured on the outer surface. A sensor element for detecting the concentration of a specific gas in the gas to be measured;
A housing for supporting and fixing the sensor element in the measured gas flow path;
A heater inserted and arranged in the sensor element;
An insulator made of an insulating material for inserting and holding the base end portion of the heater;
A metal heater holder that holds the heater, fixes the heater to the sensor element, and is electrically connected to the reference electrode of the sensor element;
A reference side signal line electrically connected to the reference electrode through the heater holder, and a measurement side signal line electrically connected to the measurement electrode;
The heater holder includes a main body portion that partially grips the heater and partially covers the heater, and a terminal portion that extends from the main body portion to the proximal end side and is electrically connected to the reference-side signal line. ,
The terminal portion of the heater holder is inserted into a terminal hole provided in the insulator,
The base end side of the body portion of the heater holder, together with the base end portion of the heater in a state of holding the heater on the inside, is partially inserted into the interpolation Hamaana of the insulator,
The main body portion of the heater holder is formed with a locking portion for locking to the end surface of the insulator in a state where the base end side of the main body portion is inserted into the insertion hole of the insulator with a predetermined length. (1).

According to a second aspect of the present invention, in the gas sensor manufacturing method of the first aspect,
The proximal end side of the heater holder holding the heater inside is inserted into the insertion hole of the insulator from the distal end side, and the engagement portion of the heater holder is brought into contact with and engaged with the distal end side end surface of the insulator. The present invention resides in a gas sensor manufacturing method (claim 6).

In the gas sensor of the first invention, as described above, not only the terminal portion of the heater holder is inserted into the terminal hole provided in the insulator, but also the base end side of the main body portion of the heater holder is The base end of the heater is partially inserted into the insertion hole of the insulator.
Therefore, when the heater holder and the insulator are assembled, the position in the radial direction can be determined by inserting the proximal end side of the heater holder into the insertion hole as described above. Therefore, no axis alignment is required, and the insulator and the heater holder can be easily assembled. Moreover, since positioning becomes easy, it can prevent that the lead wire for conducting electricity with a heater bends at the time of an assembly | attachment.

  Further, since the base end side of the main body portion is inserted into the insertion hole of the insulator together with the base end portion of the heater, the heater holder is firmly held also on the base end side. Therefore, vibration resistance is improved. Accordingly, disconnection of the lead wire for the heater due to vibration can be prevented, and the reliability of the gas sensor can be improved.

The main body portion of the heater holder is formed with a locking portion for locking to the end surface of the insulator in a state where the base end side of the main body portion is inserted into the insertion hole of the insulator with a predetermined length. Yes.
Therefore, positioning in the axial direction can also be performed. That is, the length of the heater holder inserted into the insertion hole of the insulator and the length of the heater held by the heater holder can be determined by the locking portion.

  Thus, according to the first aspect, it is possible to provide a gas sensor that can easily assemble the insulator and the heater holder.

In the second invention, the proximal end side of the heater holder holding the heater inside is inserted into the insertion hole of the insulator from the distal end side.
Therefore, the position in the radial direction can be easily determined, and the insulator and the heater holder can be easily assembled without performing axis alignment.
Moreover, the said latching | locking part of the said heater holder is made to contact | abut on the front end side end surface of the said insulator, and is latched.
Therefore, positioning in the axial direction can also be performed. That is, the length of the heater holder inserted into the insertion hole of the insulator and the length of the heater held by the heater holder can be determined by the locking portion.

  Thus, according to the second aspect of the present invention, it is possible to provide a method of manufacturing a gas sensor that can easily assemble the insulator and the heater holder.

1 is a longitudinal sectional view of a gas sensor in Embodiment 1. FIG. FIG. 3 is an explanatory diagram illustrating an overall structure of a heater holder that holds a heater in the first embodiment. FIG. 3 is an explanatory view showing a cross section in the radial direction of a heater holder that holds a heater in Embodiment 1, and is a cross-sectional view taken along line AA in FIG. 2, a cross-sectional view taken along line BB in FIG. CC sectional view (c) in FIG. 2, DD sectional view (d) in FIG. 2, EE sectional view (e) in FIG. FIG. 3 is a perspective view of a heater holder in the first embodiment. FIG. 3 is an explanatory diagram illustrating a state where the heater assembled to the heater holder is inserted into the sensor element in the first embodiment. The side view (a) of the insulator in Example 1, the bottom view (b) of an insulator, and the top view (c) of an insulator. Explanatory drawing which shows a mode that the insulator by which the heater holder was inserted in Example 1 was seen from the front end side end surface. It is explanatory drawing which shows the process of assembling a heater in a heater holder in Example 1, Comprising: (a) which shows a mode that a heater is inserted in a heater holder from the side, Explanatory drawing (b) which shows the state assembled | attached to the heater holder . FIG. 6 is an explanatory diagram illustrating an overall structure of a heater holder that holds a heater in Embodiment 2. 9A and 9B are explanatory views showing a radial cross section of a heater holder that holds a heater in Example 2, which is a cross-sectional view taken along line AA in FIG. 9, a cross-sectional view taken along line BB in FIG. 9, and FIG. CC sectional view (c) in FIG. 9, DD sectional view (d) in FIG. 9, EE sectional view (e) in FIG. The longitudinal cross-sectional view of the conventional gas sensor.

Next, a preferred embodiment of the present invention will be described. In the present specification, the gas sensor will be described with the side exposed to the gas to be measured as the distal end side and the opposite side as the proximal end side.
Examples of the gas sensor include an air-fuel ratio sensor that is installed in an exhaust pipe of an internal combustion engine for various vehicles such as an automobile engine and used for an exhaust gas feedback system, and an oxygen sensor that measures an oxygen concentration in exhaust gas.

The gas sensor is formed in a cylindrical shape with a bottom, and includes an ion conductive solid electrolyte body in which a reference electrode in contact with a reference gas is formed on an inner surface and a measurement electrode in contact with a gas to be measured is formed on an outer surface. A sensor element for detecting the concentration of the specific gas in the measurement gas is included. Examples of the bottomed cylindrical shape include a bottomed cylindrical shape.
The gas sensor includes a heater that is inserted and arranged in the sensor element, specifically, the bottomed cylindrical solid electrolyte body.
The heater can be constituted by, for example, a rod-shaped (columnar) ceramic heater. The heater generates heat by electrical conduction, and a pair of lead wires for conducting electricity can be formed on the side surface of the heater.

The gas sensor includes an insulator made of an insulating material for inserting and holding a base end portion of the heater, and holds the heater, fixes the heater to the sensor element, and the reference electrode of the sensor element. An electrically conductive metal heater holder.
The heater holder includes a main body part that partially grips the heater and partially covers the heater, and a terminal part that extends from the main body part to the proximal end side and is electrically connected to the reference-side signal line. .

The main body portion of the heater holder includes an insertion portion to be inserted into the insertion hole of the insulator, the locking portion, a grip portion for gripping the heater, and the solid electrolyte body in the sensor element. It is preferable to include at least an element fixing portion that contacts the inner side surface and fixes the heater holder to the sensor element and that is electrically connected to the reference electrode.
In this case, the performance of the heater holder can be fully utilized. That is, the heater holder can be fixed to the insulator by inserting the insertion portion into the insertion hole of the insulator. Further, the heater can be fixed to the heater holder by gripping the side surface of the heater with the gripping portion. Further, the heater holder can be fixed to the sensor element by inserting the element fixing portion into the bottomed cylindrical solid electrolyte body of the sensor element. At this time, for example, the element fixing portion of the heater holder can be electrically connected to the reference electrode formed on the inner surface of the solid electrolyte body.
Moreover, the said latching | locking part can be formed, for example by making a part of the said exterior outside project in a radial direction.

The main body portion of the heater holder includes a spine portion extending in an axial direction, a pair of insertion portions extending from the spine portion toward the heater in a direction substantially perpendicular to the axial direction, and the axial portion substantially perpendicular to the axial direction. A pair of the grip portions extending from the spine portion to the heater side, a pair of the element fixing portions extending from the spine portion to the heater side substantially perpendicular to the axial direction, and a radial direction of the gas sensor from the spine portion A pair of extending locking portions, and the insertion portion, the gripping portion, and the element fixing portion have an opening in which a side surface facing the spine portion opens in the same direction. Preferred (claim 3).
In this case, the heater can be easily assembled to the heater holder.
In other words, the main body of the heater holder has an opening whose side facing the spine opens in the same direction. Therefore, the heater can be assembled to the heater holder by inserting the side surface of the heater from the opening of the heater holder.

The main body portion of the heater holder includes a pressing portion that presses the heater in the radial direction of the gas sensor on the tip side, and at least the tip portion of the heater is in contact with the inner surface of the sensor element by the pressing portion. (Claim 4).
In this case, not only can the base end of the heater be fixed to the insulator as described above, but also the tip of the heater can be fixed to the sensor element.
Therefore, the vibration resistance of the gas sensor can be further improved.

It is preferable that the main body portion of the heater holder has a distal end extending portion extending from the spine portion toward the distal end side in the axial direction, and the pressing portion is formed in the distal end extending portion. 5).
In this case, a portion closer to the tip of the heater can be pressed by the pressing portion. Therefore, the tip of the heater can be brought into contact with the inner surface of the sensor element more reliably. Therefore, the vibration resistance of the sensor can be improved more reliably.

Next, in the gas sensor manufacturing method, the proximal end side of the heater holder holding the heater inside is inserted into the insertion hole of the insulator from the distal end side, and the locking portion of the heater holder is inserted into the insulator holder. The front end side end surface is brought into contact with and locked.
The body portion of the heater holder includes a backbone portion extending in the axial direction, a pair of insertion portions extending from the backbone portion toward the heater in a direction substantially perpendicular to the axial direction, and a direction substantially perpendicular to the axial direction. A pair of gripping portions extending from the spine portion to the heater side, a pair of element fixing portions extending from the spine portion to the heater side in a direction substantially perpendicular to the axial direction, and a diameter of the gas sensor from the spine portion. A pair of the locking portions extending in the direction, and the insertion portion, the gripping portion, and the element fixing portion have an opening portion whose side surface facing the spine portion opens in the same direction. It is preferable that the heater is assembled to the heater holder by inserting the heater from the side surface through the opening of the heater holder.
In this case, the heater can be assembled to the heater holder by inserting the side surface of the heater from the opening of the heater holder. Therefore, assembly becomes easy.

Example 1
Next, the gas sensor 1 concerning the Example of this invention is demonstrated using FIGS.
As shown in FIG. 1, the gas sensor 1 of this example includes at least a sensor element 2, a housing 3, a heater 4, an insulator 5, a heater holder 6, a reference side signal line 71, and a measurement side signal line 72. .

  The sensor element 2 is formed in a cylindrical shape with a bottom, an ion conductive solid electrolyte in which a reference electrode 215 in contact with the reference gas is formed on the inner surface 21 and a measurement electrode 225 in contact with the gas to be measured is formed on the outer surface 22. It consists of a body 20. The housing 3 supports and fixes the sensor element 2 in the measurement gas flow path. The heater 4 is inserted into the solid electrolyte body 20 of the sensor element 2 and heats the sensor element 2. The insulator 5 is made of an insulating material that inserts and holds the base end portion 41 of the heater 4. The heater holder 6 holds the heater 4, fixes the heater 4 to the sensor element 2, and is electrically connected to the reference electrode 215 of the sensor element 2. The reference signal line 71 is electrically connected to the reference electrode 215 of the sensor element 2 via the heater holder 6, and the measurement signal line 72 is electrically connected to the measurement electrode 225 via a terminal and a lead described later. Conduct.

  As shown in FIGS. 1 to 4, the heater holder 6 includes a main body portion 61 that partially holds the heater 4 and partially covers the heater 4, and extends from the main body portion 61 to the base end side to the reference-side signal line 71. The terminal portion 62 is electrically conductive. A terminal portion 62 of the heater holder 61 is inserted into a terminal hole 52 provided in the insulator 5. Further, the base end side of the main body portion 61 of the heater holder 6 is partially inserted into the insertion hole 51 of the insulator 5 together with the base end portion 41 of the heater 4 with the heater 4 held inside. The main body 61 is formed with a locking portion 612 that is locked to the distal end side end surface 562 of the insulator in a state where the base end side is inserted into the insertion hole 51 of the insulator 5 with a predetermined length. 2 is a side view of the heater holder holding the heater inside, and FIGS. 3A to 3E are AA line, BB line, CC line, D in FIG. 2, respectively. It is a figure which shows the cross-sectional shape when the cross section of the -D line and the EE line is seen by the arrow.

Hereinafter, the gas sensor 1 of this example will be described in detail.
As shown in FIG. 1, in the gas sensor 1, the sensor element 2 is held inside a cylindrical housing 3.
The sensor element 2 includes, for example, a solid electrolyte body 20 formed in a bottomed cylindrical shape whose end is closed with an oxygen ion conductive material such as zirconia, a reference electrode 215 formed on the inner surface 21, and an outer surface 22. Measurement electrode 225. A solid electrolyte body engaging portion 201 having a large diameter is formed in the middle of the solid electrolyte body 20.

A metal heater holder 6 is inserted into the solid electrolyte body 20.
In this example, as shown in FIGS. 1 to 4, the heater holder 6 includes a substantially cylindrical main body 61 that partially grasps the heater 4 and partially covers the heater 4, and a proximal end side from the main body 61. The terminal portion 62 extends and is electrically connected to the reference signal line 71. The terminal portion 62 is formed in a substantially cylindrical shape having an open side surface so that a reference side signal line 71 extending from the reference side of the gas sensor 1 is inserted and held at the base end side.

The main body 61 of the heater holder 6 includes an insertion portion 611, a locking portion 612, a grip portion 613, and an element fixing portion 614 in order from the proximal end side to the distal end side. Specifically, the main body 61 includes a spine portion 610 extending in the axial direction, a pair of insertion portions 611 extending from the spine portion 610 toward the heater 4 in a direction substantially perpendicular to the axial direction, and an axial direction substantially perpendicular to the axial direction. A pair of grip portions 613 extending from the spine portion 610 to the heater side, a pair of element fixing portions 614 extending from the spine portion 610 to the heater side in a direction substantially perpendicular to the axial direction, and a pair extending from the spine portion 610 in the radial direction of the gas sensor 1. And a locking portion 612. The insertion part 611, the grip part 613, the element fixing part 614, and the locking part 612 have an opening part 619 whose side face facing the spine part opens in the same direction. In addition, the latching | locking part 612 is formed so that it may extend in the direction opposite to the heater 4 side from the backbone part 610, and the heater 4 side is necessarily opened. That is, the main body 61 of the heater holder 6 has a substantially C-shaped cross section in the radial direction of the gas sensor.
The main body 61 of the heater holder 6 has a distal end extending portion 63 that extends from the spine 610 to the distal end in the axial direction. A pressing portion 635 that presses the heater 4 in the radial direction of the gas sensor 1 is formed on the distal end side of the distal end extending portion 63.

  In the gas sensor 1, the heater holder 6 is inserted into the solid electrolyte body 20 from the distal end side in a state where the heater 4 is gripped by the grip portion 613. The heater holder 6 is fitted inside the solid electrolyte body 20 at the element fixing portion 614. The heater holder 6 is electrically connected to a reference electrode 215 formed on the inner surface 21 of the solid electrolyte body 20 at the element fixing portion 614. The measurement electrode 225 formed on the outer surface of the solid electrolyte body 20 is electrically connected to the measurement-side intermediate lead 721 extending to the base end side.

The heater 4 is assembled to the main body 61 of the heater holder 6. The heater 4 is held by a holder at a holding portion 613 of the heater holder 6, and the heater 4 is fixed to the heater holder 6.
The heater 4 includes a heater base formed of a ceramic material such as alumina in the shape of a long axis, a heating element (not shown) built in the tip, and a pair of lead wires (not shown) connected to the heating element. And a pair of heater electrodes 45 formed on the surface of the heater substrate and respectively conducting to the pair of lead wires.
The heater 4 is inserted into the sensor element 2 and is elastically fixed by a grip portion 613 of the heater holder 6.
Moreover, as shown in FIG. 5, the pressing part 635 of the heater holder 6 presses the side surface of the heater 4 in the radial direction of the gas sensor. Thereby, the front end portion 42 of the heater 4 is in contact with the inner side surface 21 of the solid electrolyte body 20.

  As shown in FIG. 1, the housing 3 is formed with a housing engaging portion 31, and the solid electrolyte body engaging portion 201 and the housing engaging portion 31 are connected via a metal buffer member (not shown). The sensor element 2 is engaged and locked in the housing 3. Further, in the gap between the sensor element 2 and the housing 3, for example, an insulating powder 101 such as talc, an insulating powder molded body 102, an insulating sealing member 103 such as ceramic or glass, a spacer made of a metal member The sensor element 2 is filled with an element fixing member 104, and the housing caulking portion 32 at the upper edge of the housing 3 is caulked to fix the sensor element 2 in the housing 3.

An element cover 12 that protects the sensor element 2 is fixed to the front end side of the housing 3. The element cover 12 has a double structure in which two covers of an inner cover 121 and an outer cover 122 are arranged in parallel. The inner cover 121 and the outer cover 122 are formed with measured gas inlets 127 and 128 for introducing the measured gas into them, respectively.
As a result, the gas to be measured flowing through the exhaust system of the internal combustion engine is introduced into the gas chamber 120 to be measured formed inside the element cover 12 and around the sensor element 2 through the gas introduction ports 127 and 128. be able to.

As shown in FIG. 1, the gas sensor 1 includes, on the proximal end side, a reference side signal line 71 and a measurement side signal line 72 connected to an external circuit, an insulator 5, an insulator holding metal fitting 50, and a reference gas side cover 13. Are arranged.
The reference gas side cover 13 is fixed to the proximal end side of the housing 3 and forms a reference gas space 130 on the inner side. In other words, the opening on the front end side of the reference gas side cover 13 is welded to the cover fixing portion 34 disposed on the radially outer side of the caulking portion 32 in the housing 3. The base end portion of the reference gas side cover 13 is sealed with a rubber bush 16. The reference signal line 71 and the measurement signal line 72 connected to the external circuit are insulated and supported by the rubber bush 16.

The structure of the insulator 5 is shown to Fig.6 (a)-(c).
As shown in the figure, the insulator 5 is made of an insulating material, and has a cylindrical main body portion 56 and a substantially cylindrical protrusion portion 57 extending from the base end side end surface 561 of the main body portion 56 to the base end side. It is a substantially convex member. An insertion hole 51 for inserting and holding the proximal end portion of the heater is provided on the distal end side end surface 562 of the insulator 5 in the axial direction. The insertion hole 51 does not penetrate the insulator 5 and is closed so that the base end portion of the heater abuts inside the insulator 5. Further, the insulator 5 is connected to a reference-side terminal hole 52 into which a terminal portion 62 (see FIGS. 2 to 4) extending from the main body portion 61 of the heater holder 6 to the proximal end side in the axial direction is inserted, and a measurement-side intermediate lead 721. The measurement-side terminal holes 53 into which the measurement-side terminals 722 (see FIG. 1) to be inserted are respectively formed on the outer side in the radial direction from the insertion holes 51. The reference side terminal hole 52 and the measurement side terminal hole 53 penetrate the body portion 56 of the insulator 5 in the axial direction. The insulator 5 is also formed with a pair of heater lead holes 511 and 512 into which a pair of lead portions 451 (see FIG. 1) extending from the heater electrode 45 and projecting in the axial direction are inserted at the base end portion 41 of the heater 4. Has been. The heater lead holes 511 and 512 are integrated with the insertion hole 51 on the tip side of the insulator, and the protrusion 57 is formed by a hole independent of the insertion hole 51. The heater lead hole passes through the main body portion 56 and the protruding portion 57 in the axial direction.

  As shown in FIG. 1, the insulator 5 is fixed in the reference gas side cover 13 by a holding metal fitting 50. And the base end part 41 of the heater 4 is inserted in the insertion hole 51 of the insulator 5 with the insertion part 611 of the heater holder 6.

FIG. 7 shows a state where the state in which the insertion portion 611 of the heater holder 6 is inserted into the insulator 5 is observed from the end surface 562 of the insulator. In the figure, members other than the insulator 5, the heater holder 6, and a measurement side terminal 722 described later are omitted.
As shown in FIG. 7, an insertion portion 611 formed on the base end side of the main body portion of the heater holder 6 is inserted into the insertion hole 51 of the insulator 5 together with the base end portion of the heater (not shown, see FIG. 1). . The heater holder 6 is fixed to the insulator 5 by fitting the insertion portion 611 of the heater holder 6 with the insertion hole 51 of the insulator 5. Further, the engaging portion 612 of the heater holder 6 is in contact with the tip end surface 562 of the insulator 5. Thereby, the length of the heater holder 6 inserted in the insertion hole 51 is adjusted.
As shown in FIGS. 1 and 7, a pair of lead portions 451 extending from a pair of heater electrodes 45 formed on the base end side of the outer peripheral portion of the heater 4 are inserted into the heater lead holes 511 and 512. . These lead portions 451 are connected to a heater power supply lead 49 extending from an external power supply (not shown), so that power can be supplied to the heater from the external power supply.

As shown in FIGS. 1 and 7, a reference side terminal 62 integrally connected to the main body of the heater holder 6 is inserted into the reference side terminal hole 52 of the insulator 5. The reference terminal 62 is electrically connected to a reference signal line 71 extending from the base end side of the gas sensor 1.
As shown in FIGS. 1 and 7, the measurement side terminal 722 is inserted into the measurement side terminal hole 53 of the insulator 5. The measurement side terminal 722 is formed by forming an elastic metal material into a substantially U-shaped spring shape. The measurement side terminal 722 is electrically connected to the measurement side intermediate lead 721 on the distal end side as described above, and is electrically connected to the measurement side signal line 72 extending from the proximal end side of the gas sensor 1 on the proximal end side. Has been.

  As shown in FIG. 1, a caulking cover 14 is disposed on the outer peripheral side of the reference gas side cover 13, and the caulking cover 14 is caulked and fixed to the reference gas side cover 13. In addition, the caulking cover 14 is formed with a reference gas introduction port 141 for introducing a reference gas into the reference gas space 130.

  Note that the reference gas is the atmosphere, and the atmosphere flowing in from the reference gas inlet 141 passes through the reference gas space 130 in the reference gas side cover and flows into the reference gas chamber 20 in the sensor element.

Next, in the gas sensor 1 of this example, a method of assembling the heater to the heater holder will be described with reference to FIG.
In this example, as shown in FIG. 4, FIG. 8A and FIG. 8B, the main body 61 of the heater holder 6 includes a spine 610 extending in the axial direction and a spine portion on the heater 4 side in a direction substantially perpendicular to the axial direction. A pair of insertion portions 611 extending from 610, a pair of gripping portions 613, and a pair of element fixing portions 614 are provided. Further, the main body 61 has a pair of locking portions 612 extending from the spine portion 610 in the radial direction of the gas sensor. The insertion portion 611, the grip portion 613, the element fixing portion 614, and the locking portion are open in the same direction on the side surface facing the spine portion.
Therefore, the heater 4 can be assembled to the heater holder 6 by inserting the heater 4 from the side of the opening 619 of the heater holder 6.

Hereinafter, the effect of the gas sensor 1 of this example is demonstrated using FIGS.
In the gas sensor 1 of this example, as described above, the terminal portion 62 of the heater holder 6 is not only inserted into the terminal hole 52 provided in the insulator 5, but the base end side of the main body portion 61 of the heater holder 6 is connected to the heater. The base end part 41 of 4 is partially inserted in the insertion hole 51 of the insulator 5.
Therefore, when the heater holder 6 and the insulator 5 are assembled, the radial position can be determined by inserting the insertion portion 611 of the heater holder 6 into the insertion hole 51 as described above. Therefore, no axis alignment is required, and the insulator 5 and the heater holder 6 can be easily assembled. Moreover, since positioning becomes easy, it can prevent that the lead wire for conducting electricity to the heater 4 is bent at the time of assembly.

  Further, since the base end side of the main body portion 61 is inserted into the insertion hole 51 of the insulator 5 together with the base end portion 41 of the heater 4, the heater holder 6 and the heater 4 are firmly held on the base end side by the insulator 5. The Therefore, vibration resistance is improved. Accordingly, disconnection of the heater lead portion 451 due to vibration can be prevented and the reliability of the gas sensor 1 can be improved.

Further, the main body 61 of the heater holder 6 is formed with a locking portion 612 that is locked to the end surface 562 of the insulator 5 in a state where the base end side is inserted into the insertion hole 51 of the insulator 5 with a predetermined length. Yes.
Therefore, positioning in the axial direction can also be performed. That is, the length of the heater holder 6 inserted into the insertion hole 51 of the insulator 5 can be determined by the locking portion 612.

In this example, the main body 61 of the heater holder 6 includes an insertion portion 611 that is inserted into the insertion hole 51 of the insulator 5, a locking portion 612, a grip portion 613 that grips the heater, and the sensor element 2. The heater holder 6 is fixed to the sensor element 2 by being fitted to the inner side surface 21 of the inner solid electrolyte body 20, and at least an element fixing portion 614 that is electrically connected to the reference electrode 215 is provided.
Therefore, the performance of the heater holder 6 can be fully utilized. That is, the heater holder 6 can be fixed to the insulator 5 by inserting the insertion portion 611 into the insertion hole 51 of the insulator 5. Further, the heater 4 can be fixed to the heater holder 6 by gripping the side surface of the heater 4 with the grip portion 613. The heater holder 6 can be fixed to the sensor element 2 by inserting the element fixing portion 614 into the bottomed cylindrical solid electrolyte body 20 of the sensor element 2. At this time, for example, the element fixing portion 614 of the heater holder 6 can be electrically connected to the reference electrode 215 formed on the inner surface of the solid electrolyte body 20.

The main body 61 of the heater holder 6 includes a spine portion 610 extending in the axial direction, a pair of insertion portions 611 extending from the spine portion 610 toward the heater side in a direction substantially perpendicular to the axial direction, and a heater in a direction substantially perpendicular to the axial direction. A pair of gripping portions 613 extending from the spine portion 610 to the side, a pair of element fixing portions 614 extending from the spine portion 610 to the heater side substantially perpendicular to the axial direction, and a pair extending from the spine portion 610 in the radial direction of the gas sensor The insertion part 611, the gripping part 613, the element fixing part 613, and the locking part 612 have an opening part 619 whose side facing the spine part 610 opens in the same direction. ing.
Therefore, the heater 4 can be assembled to the heater holder 6 by inserting the side surface of the heater 4 from the opening 619 of the heater holder 6 (see FIG. 8). Therefore, the heater 4 can be easily assembled to the heater holder 6.

The main body 61 of the heater holder 6 includes a pressing portion 635 that presses the heater 4 in the radial direction of the gas sensor 1 on the distal end side. Abutting (see FIG. 5).
Therefore, the tip 42 of the heater 4 can be fixed to the sensor element 2. Therefore, the vibration resistance of the gas sensor 1 can be further improved.

The main body 61 of the heater holder 6 has a distal end extending portion 63 that extends from the spine 610 toward the distal end in the axial direction, and the pressing portion 635 is formed in the distal end extending portion 63.
Therefore, a portion closer to the tip portion of the heater 4 can be pressed by the pressing portion. Therefore, the tip end portion 42 of the heater 4 can be brought into contact with the inner side surface 21 of the sensor element 2 more reliably. Therefore, the vibration resistance of the sensor 1 can be improved more reliably.

(Example 2)
This example is an example of a gas sensor in which the shape of the heater holder is different from that of the first embodiment.
In the gas sensor of this example, as shown in FIGS. 9 and 10, the heater holder 8 includes a main body 81 that partially grips the heater 4 and partially covers the heater 4, as in the first embodiment, and a main body 81. Terminal portion 82 extending from the base end side to the base end side and electrically conducting to the reference side signal line.

  Similar to the first embodiment, the main body 81 of the heater holder 8 includes an insertion portion 811, a locking portion 812, a gripping portion 813, and an element fixing portion 814. Further, the heater holder 8 has a distal end extending portion 83 extending from the spine portion 810 to the distal end side in the axial direction, and a pressing portion 835 is formed at the distal end of the distal end extending portion 83.

In this example, the main body 81 of the heater holder 8 has a cylindrical shape with one side surface opened as a whole. As shown in FIGS. 9 and 10, the diameter of the cylindrical main body 81 is formed in such a size that the insertion portion 811 and the element fixing portion 814 of the main body 81 are inserted into the insertion hole of the insulator and the sensor element. Has been. The locking portion 812 is formed by partially extending the end of the opening in the cylindrical main body portion in the radial direction of the gas sensor. As a result, the locking portion 812 and the insertion portion 811 are formed on the proximal side of the locking portion 812.
Further, the gripping portion 813 is formed by partially hollowing out the side surface of the cylindrical main body portion and bending the side surface partially inward in the radial direction.
Other configurations are the same as those of the first embodiment.

Although the heater holder 8 of this example is different in the shape of the holder from that of the first embodiment, the insertion part 811, the grip part 812, the element fixing part 813, and the locking part 814 are open in the same direction on the side face facing the spine part. An opening 819 is formed.
Therefore, similarly to the first embodiment, the heater 4 can be assembled to the heater holder 8 by inserting the side surface of the heater 4 from the opening 819 of the heater holder 8. Therefore, assembly of the heater 4 to the heater holder 8 is facilitated.
Other functions and effects are the same as those of the first embodiment.

DESCRIPTION OF SYMBOLS 1 Gas sensor 2 Sensor element 3 Housing 4 Heater 41 (End of heater) 5 Insulator 51 Insertion hole 6 Heater holder 611 Insertion part 612 Locking part 635 Pressing part

Claims (7)

It consists of an ion-conductive solid electrolyte body formed with a bottomed cylinder, a reference electrode in contact with the reference gas is formed on the inner surface, and a measurement electrode in contact with the measured gas on the outer surface. A sensor element for detecting the concentration of a specific gas;
A housing for supporting and fixing the sensor element in the measured gas flow path;
A heater inserted and arranged in the sensor element;
An insulator made of an insulating material for inserting and holding the base end portion of the heater;
A metal heater holder that holds the heater, fixes the heater to the sensor element, and is electrically connected to the reference electrode of the sensor element;
A reference side signal line electrically connected to the reference electrode through the heater holder, and a measurement side signal line electrically connected to the measurement electrode;
The heater holder includes a main body portion that partially grips the heater and partially covers the heater, and a terminal portion that extends from the main body portion to the proximal end side and is electrically connected to the reference-side signal line. ,
The terminal portion of the heater holder is inserted into a terminal hole provided in the insulator,
The base end side of the body portion of the heater holder, together with the base end portion of the heater in a state of holding the heater on the inside, is partially inserted into the interpolation Hamaana of the insulator,
The main body portion of the heater holder is formed with a locking portion for locking to the end surface of the insulator in a state where the base end side of the main body portion is inserted into the insertion hole of the insulator with a predetermined length. A gas sensor.   2. The gas sensor according to claim 1, wherein the main body portion of the heater holder includes an insertion portion that is inserted into the insertion hole of the insulator, the locking portion, a holding portion that holds the heater, and A gas sensor comprising at least an element fixing portion that contacts the inner side surface of the solid electrolyte body in the sensor element and fixes the heater holder to the sensor element and is electrically connected to the reference electrode. .   The gas sensor according to claim 2, wherein the main body portion of the heater holder includes a spine portion extending in an axial direction, and a pair of insertion portions extending from the spine portion toward the heater in a direction substantially perpendicular to the axial direction. A pair of grips extending from the spine to the heater side in a direction substantially perpendicular to the axial direction; a pair of element fixing parts extending from the spine to the heater in a direction substantially perpendicular to the axial direction; A pair of locking portions extending in the radial direction of the gas sensor from the spine portion, and the insertion portion, the grip portion, and the element fixing portion open in the same direction on the side face facing the spine portion. A gas sensor having an opening.   The gas sensor according to any one of claims 1 to 3, wherein the main body portion of the heater holder includes a pressing portion that presses the heater in a radial direction of the gas sensor on a distal end side, and the heater causes the heater to be at least A gas sensor characterized in that a tip portion is in contact with an inner surface of the sensor element.   5. The gas sensor according to claim 4, wherein the main body portion of the heater holder has a distal end extending portion that extends from the spine portion toward an axial distal end side, and the pressing portion is formed in the distal end extending portion. Gas sensor characterized by being made. In the manufacturing method of the gas sensor of Claims 1-5,
The proximal end side of the heater holder holding the heater inside is inserted into the insertion hole of the insulator from the distal end side, and the engagement portion of the heater holder is brought into contact with and engaged with the distal end side end surface of the insulator. A method for producing a gas sensor.   7. The method of manufacturing a gas sensor according to claim 6, wherein the main body portion of the heater holder includes a spine portion extending in an axial direction and a pair of insertions extending from the spine portion toward the heater in a direction substantially perpendicular to the axial direction. A pair of gripping portions extending from the spine portion to the heater side in a direction substantially perpendicular to the axial direction, and a pair of element fixing portions extending from the spine portion to the heater side in a direction substantially perpendicular to the axial direction And a pair of the locking portions extending in the radial direction of the gas sensor from the spine portion, and the side faces of the insertion portion, the grip portion, and the element fixing portion facing the spine portion are in the same direction. A method of manufacturing a gas sensor, comprising: an opening formed in the heater holder; and the heater is assembled to the heater holder by inserting the heater from the side through the opening of the heater holder. .

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